Skylight with multi-layer polymeric panel

ABSTRACT

A skylight is formed with a pair of plastic panels having outer peripheral flanges and a central region transparent to visible light, aligned in a stacked orientation with the peripheral flanges overlying one another and defining an enclosed central region in-between. An inner and outer pair of circumferentially oriented spacer frames are interposed between and bonded to the outer peripheral flanges of elastic panels to form a sealed enclosed region. A peripheral frame is formed in situ about the plastic panels from a moldable polymeric material which entraps the peripheral flanges forming an integral leakproof structure with the spacer frames preventing intrusion of the moldable polymeric frame material into the enclosed region.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a window containing structures having amolded polymeric frame extending about the outer peripheral flange of apair of spaced apart light transparent plastic panels.

2. Background Art

Window containing structures in buildings such as a skylights, windowassemblies and certain types of doors, are typically formed of a lighttransparent panel of glass or plastic mounted in a peripheral frameformed of wood, metal or extruded plastic. In order to provide goodthermal insulation, two spaced apart transparent layers are frequentlyutilized creating an enclosed region there between which is filled withgas. Windows and doors typically use a pair of glass transparent panelsjoined together about their outer peripheral edge by a spacer forming aninsulated glass unit (IGU). Skylights can alternatively be formed withglass panels or plastic panels. Since skylights typically do not requirethe same degree of optical quality as windows, low cost and light weightplastic panels can be utilized in place of glass. In order to achievestructural rigidity, the plastic panels are frequently, outwardly, domedin a convex manner, the peripheral edges of the plastic panels mountedin a rectangular or circular mounted frame. Typically, the periphery ofthe plastic panels are attached to the frame interposed between a framecurb portion and a mounting flange and held together by a series offasteners.

In U.S. patent publication application No. 2005-0178078-A1 publishedAug. 18, 2005, which is incorporated by reference in its entirety, awindow containing assembly with a molded plastic frame is disclosed.Several embodiments provide a peripheral polymeric frame molded about amulti-layer light transparent panel of glass or plastic. A spacer/sealjoins the panels and prevents plastic from intruding into the internalcentral region of the panel assembly during molding.

SUMMARY OF THE INVENTION

It is an object of the present invention to manufacture windows having amolded plastic frame and a multi-layer plastic skylight panel. It istherefore important to prevent intrusion of the moldable plastic framematerial into the central region of the overlapping plastic panels. Itis necessary to have a good seal when the mold is closed between thespacer and the peripheral plastic panels. When plastic panels are vacuumformed or sag bent into a dome shape, it is common to have somevariations in the peripheral flange flatness, particularly in the cornerregions. These variations in flatness between adjacent plastic panelscan result in a leak path enabling polymeric material to intrude intothe central region of the light transmission layer pair which canadversely affect frame strength as well as providing an unsightlyprotrusion into the visible area of the window.

It is an object of the present invention to provide a skylight having agood seal between the outer peripheral flanges of the plastic lighttransparent panels to prevent intrusion of the moldable plastic materialof the frame during the molding process into the enclosed region of theplastic panels, while accommodating normally occurring flatnessvariations between panels resulting from plastic panel thermoforming.

It is a further desired to significantly space apart the edges of theplastic panels to achieve an assembled finished edge thicknessapproximate that of a glass IGU so that both glass and plastic glazingpanel skylights can be made in the same mold.

Accordingly a glazing unit is provided having a pair of plastic lighttransparent panels aligned in stacked relation having cooperating outerperipheral flanges which overlie one another. The outer peripheralflanges are bonded together utilizing a tubular metal spacer positionedthere between and bonded to the plastic panels. A peripheral frame isthen formed in situ of a molded polymeric material about the pair ofplastic panels entrapping the peripheral flanges forming a leak tightstructure.

The glazing unit of the present invention is particularly well suitedfor use as a skylight in both small residential and large commercialapplications. The tubular metal spacer is bonded to the pair of plasticpanels to align the panels, seal their outer periphery and to make theassembly easy to handle when inserting into a mold. The mold is thenclosed and a moldable polymeric material is introduced into the moldcavity forming a unitary peripheral flange in situ about the peripheraledge of the plastic panels.

In one of the embodiments of the invention illustrated, the pair ofplastic light transmitting panels are formed of acrylic. The tubularspacer is made of thin wall aluminum segments joined by corner keys intothe shape of a rectangle and bonded to the spaced apart panel flanges.Once joined, the stacked sub-assembly is inserted into a mold forforming a frame thereabout. The mold is then closed and moldablepolymeric material is injected into the mold cavity forming a frame insitu which is securely bonded to the peripheral flanges of the plasticpanels forming a leak tight joint between the peripheral frame and theentrapped peripheral flanges of the transparent plastic panels. Theassembly is then removed from the mold.

In one embodiment of the invention, the method is practiced by injectinga RIM polymeric material into the mold and in another, a thermoplasticmaterial is used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a skylight assembly installed in abuilding;

FIG. 2 is a perspective view of a first skylight embodiment of theinvention;

FIG. 3 is a cross-section taken along section 3-3 of FIG. 2;

FIG. 4 is a cross-section of an alternative embodiment;

FIG. 5 is a top plan exploded partial view of a spacer corner joint;

FIG. 6 is an exploded cross-sectional side view illustrating theplacement of the spacers relative to the edges of the plastic panels;

FIG. 7 is a top plan view illustrating a joint formed in the two-sidedelastic tape strip; and

FIG. 8 is a cross-sectional view of an alternative twin spacer framemember.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for the claims and/or as a representative basis forteaching one skilled in the art to utilize the present invention.

FIG. 1 illustrates a building 10 having a sloped roof 12 on which askylight assembly 14 is mounted. The skylight assembly 14 has a centralinsulating glazing unit 16 made up of two or more pairs of plasticpanels which are at least semi-transparent to visible light. Skylight 14is further provided with a peripheral frame 18 which is molded about theperiphery of the insulating glazing unit 16. Frame 18 is affixed to thebuilding roof 12 in a weather-tight manner. Frame 18 can be mounted to aconventional skylight roof curb or as illustrated in FIGS. 2 and 3,frame 18 can be integrally formed with a curb 20 and a flashing member22. Insulating glazing unit 16 is made up of a pair of plastic panels,inner panel 24 and outer panel 26, each formed in the shape of a domeand spaced apart to define a central enclosed region 28 therebetween.Enclosed region 28 can be form filled with air or other gases, such asArgon.

The insulating glazing unit 16 has a center section 30 which is at leastsemi-transparent to visible light and a surrounding peripheral flange 32which is affixed to frame 18. The pair of plastic panels 24 and 26 eachhave a transparent central section and a corresponding peripheralflange. The peripheral flanges of the inner and outer plastic panels arejoined together by a pair of spaced apart circumferential spacer frames34 and 36. Each of the spacer frames forms a continuous loop extendingcircumferentially about and inboard of the outer peripheral-most edge ofthe pair of plastic panels 24 and 26. The outer peripheral edge of theplastic panel generally lies along a common plane 38, shown in FIG. 3,which is generally perpendicular to centerline 40 illustrated in FIGS. 2and 3. Inner spacer frame 34 is located closer to centerline 40 thanouter spacer frame 36 as illustrated in cross-sectional view. Spacerframes 34 and 36 are transversely spaced apart. The inner spacer frame34 is oriented slightly outboard of the junction between the innermostedge of frame 18 and the plastic panels 24 and 26. Outer spacer frame 36is located approximate and preferably slightly inboard of the outermostperipheral edge of the plastic panels 24 and 26.

In the embodiment illustrated in FIG. 3, the inner and outer spacerframes 34 and 36 are preferably a tubular aluminum spacer channel of thetype commonly used to form glass dual pane insulated glazing units. Thespecific aluminum rectangular spacer used has a height of 0.50 inchesand a width of 3.15 inches with a 0.10 inch wall thickness. The top andbottom of the planar surfaces of the spacers 34 and 36 are coated with apolyurethane caulk-like adhesive and the inner and outer spacers areplaced on one of the plastic panels 24 or 26. The other plastic panel isthen installed in an aligned stacked orientation securely bonding thepanels together. The inner and outer spacer frames 34 and 36 are eachgenerally rectangular in shape in plan view and are made up of fourlinear segments of tubular frame segments 42 interconnected at thecorners by corner keys 44. Corner keys 44 are plastic L-shaped membershaving flexible projections which are inserted inside of the tubularframe segments 42. An exploded cross-sectional view showing theoverlying peripheral flange of inner and outer plastic panel 24 and 26and inner and outer spacer frames 34 and 36 is illustrated in FIG. 6. Aspreviously indicated, the top and bottom surfaces of each of the innerand outer spacer frame members 34, 36 is coated with an adhesive whichis compatible with the plastic material of panels 24 and 26, as well asbeing compatible with the material of frame 18. A top plan view of acorner section of the assembled inner and outer plastic panel assemblyis shown in FIG. 7.

The panel assembly which forms an insulating glazing unit is insertedinto a mold and frame 18 is molded thereabout in situ securelyentrapping the peripheral flange 32 of the insulating glazing unit 16.The frame 18 forms a securely tight seal with the insulating glazingunit in a manner similar to that described in U.S. Patent PublicationNo. 2005-0178078, previously incorporated by reference. A preferredmaterial for forming peripheral frame 18 is a polyurethane RIM material.However, other materials, including thermoplastics, could be utilized inpracticing the invention. The structure of the present inner and outerspacer frames addresses two problems. One is the necessity to provide asecure leak-tight joint between the plastic panel peripheral flanges toprevent intrusion of polymetric material used to mold the peripheralframe 18. The second is the inner and outer space frame constructionfurther enables very substantial peripheral flange thicknesses to beachieved with an insulating and glazing unit having a plastic inner andouter panel. A thick peripheral flange enables one skylight mold to beused to produce both glass skylights, as well as domed plasticskylights. The height of the inner and outer spacer frames is selectedso that when inserted between the peripheral flanges of the outer andinner panels 24, 26 with the appropriate adhesive layers therebetween,the overall stack height of the peripheral frame approximates that of aglass thermal pane insulating glazing unit when clamped in the moldprior to plastic injection.

Inner space frame 34 provides the necessary structural rigidity when themold is clamped closed. The outer spacer frame 36 serves to securelybond the peripheral flanges of the outer and inner plastic panelstogether in a leak-tight manner and provide the necessary resistance tothe inward forces from the injected polymeric material used to formperipheral frame 18. As previously described, each of the inner andouter spacer frames are formed of a series of straight frame segments 42interconnected by corner keys 44. Preferably, the frame segments have awidth between 0.2 and 0.5 inches and a height of 0.4 to 0.8 inches.Preferably, the inner and outer spacer frames will be spacedtransversely apart 0.20 to 1.5 inches, as dictated by the selectedperipheral flange size. Preferably, the outer spacer frame is inwardlyinset relative to the outermost edge of the peripheral flange by 0.1 to0.25 inches.

The preferred spacer frame illustrated in FIGS. 3-6 is an aluminumrectangle which is roll-formed and mechanically joined into a closedtube. Alternative spacer frames can be used, such as commerciallyavailable stainless steel roll-form spacers, as well as commerciallyavailable metal/silicon foam composite spacer frames used in Argon gasfilled insulating glass units.

In the preferred embodiment, the skylight plastic outer and inner panels24 and 26 are formed of acrylic. If desired, the inner or outer plasticpanels may be coated with an optical or thermal layer in order toregulate light transmittance in the heat transfer. As an alternative toacrylic, other materials can be used, such as polycarbon or a PET. Dueto the exposure to indirect sunlight, it may be necessary to apply a UVbarrier when UV sensitive plastic panels are utilized. When fabricatingvery large skylights, it may be advantageous to include reinforcingfibers, such as chopped glass in with the moldable polymetric materialutilized to form the frame 18.

As mentioned previously, frame 18 may be integrally formed with a curb20 and a flashing 22, as illustrated in FIGS. 2 and 3. Alternatively, askylight assembly 50, illustrated in FIG. 4, may be provided with aframe 52 for mounting directly upon a pre-existing curb (not shown).When frame 52 is designed for a curb mount, a downwardly extendingmounting flange 54 may be provided on frame 52 for affixing the frame tothe curb. Conventional fasteners can be installed through a series ofmounting holes 56 provided in the mounting flange 54.

As an alternative to using separate inner and outer spacer frames 34 and36, as previously described, the inner and outer spacer frames can beformed together by making a generally figure eight shape roll form framespacer 60 illustrated in FIG. 8. The ends of elongate frame segments ofthe spacer 60 will be stair-step cut so that conventional corner keys 44can be utilized. Alternatively, a custom corner key can be fabricatedenabling the frame segments to be cut either square or mitered. Thefigure eight shaped frame spacer 60 illustrated in FIG. 8 controls thespacing between the inner and outer frame segments thereby easing theassembly process. The top and bottom surfaces of the spacer 60 areprovided with the series of shallow grooves 62 as illustrated to receivea bead of construction adhesive used to assemble the spacer framebetween the spaced-apart inner and outer plastic panel flanges. Ofcourse, a wide variety spacer frame cross-sectional designs could beutilized when practicing the present invention.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. A skylight assembly comprising: a pair of plastic panels each havinga generally similarly sized outer peripheral flange and a central regionwhich is at least semi-transparent to visible light, the pair of plasticpanels when aligned in stacked relation with the outer peripheralflanges generally overlying the inner periphery flanges; an inner andouter pair of circumferentially oriented spacer frames interposedbetween and bonded to the outer peripheral flanges of the pair ofplastic panels to form a central enclosed region which is filled withgas and bounded by the inner spacer frame and a central section of thepair of plastic panels; and a peripheral frame formed in situ of amoldable polymeric material bonded to the outer spacer frame and theperipheral flanges of the pair of plastic panels, entrapping theperipheral flanges and forming a leak tight structural joint therewith;wherein the outer spacer frame provides a seal between the peripheralflanges of the pair of plastic panels as the peripheral frame is moldedpreventing intrusion of the moldable polymeric material into the centralenclosed region.
 2. The skylight assembly of claim 1 wherein the innerand outer pair of circumferentially oriented spacer frames each have anupper and lower surface coated with adhesive.
 3. The skylight assemblyof claim 1 wherein the inner and outer pair of circumferentiallyoriented spacer frames each have a width of 0.20 to 0.50 inches.
 4. Theskylight assembly of claim 1 wherein the inner and outer pair ofcircumferentially oriented spacer frames each comprises a segment havinga hollow generally rectangle cross-section.
 5. The skylight assembly ofclaim 4 wherein the inner and outer pair of circumferentially orientedspacer frames are spaced apart 0.2 to 1.00 inches.
 6. The skylightassembly of claim 4 wherein the inner and outer pair ofcircumferentially oriented spacer frames comprise a plurality of linearsegments interconnected by corner keys to form a pair of continuousframes.
 7. The skylight assembly of claim 6 wherein the linear segmentsforming the inner and outer pair of circumferentially oriented spacerframes each have a width of 0.20 to 0.50 inches and a height of 0.40 to0.80 inches.
 8. The skylight assembly of claim 1 wherein the outerspacer frame is inwardly inset from the outer most edge of theperipheral flange by 0.10 to 0.25 inches.
 9. The skylight assembly ofclaim 1 wherein the plastic panels are formed of acrylic.
 10. Theskylight assembly of claim 1 wherein the plastic panels are formed ofpoly carbonate.
 11. The skylight assembly of claim 1 wherein theperipheral frame is formed of a RIM material.
 12. The skylight assemblyof claim 1 wherein the peripheral frame is formed of a thermoplasticmaterial.
 13. The skylight assembly of claim 1 wherein the thermoplasticmaterial is filled with reinforcing fibers.
 14. The skylight assembly ofclaim 1 wherein the peripheral frame is generally rectangular in shape.15. The skylight assembly of claim 1 wherein the outer peripheralflanges of the pair of plastic panels lie in a plane perpendicular tothe central axis.
 16. A method of forming a glazing unit comprising:forming a pair of plastic panels from a sheet of plastic material whichis at least semi-transparent to visible light, the pair of plasticpanels having an outer peripheral flange and a central region, which,when stacked upon one another, define an enclosed cavity bounded by thespaced apart central regions of the plastic panels when overlying oneanother; bonding an inner and outer pair of circumferentially orientedspacer frames between the outer peripheral flanges of the pair ofplastic panels to form a central enclosed region which is filled withgas bounded by the inner spacer frame and the pair of plastic panels;inserting the bonded pair of plastic panels into a skylight frame moldso that the mold entraps the peripheral flanges of the stacked pair ofplastic panels; injecting a moldable polymeric material into the moldforming a frame which is securely bonded to the peripheral flanges ofthe plastic panels and the outer spacer frame wherein the outer spacerframe prevents the a moldable polymeric material from entering into thecentral region formed between the plastic panels; and removing theskylight assembly from the mold.
 17. The method of claim 16 wherein themoldable polymeric material comprises RIM.
 18. The method of claim 16wherein the moldable polymeric material comprises a thermoplastic. 19.The method of claim 16 wherein the pair of plastic panels are formed ofacrylic.